Javascript 如何检查对象是否具有函数？(道场)
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How to check if an object has a function? (DoJo)
提问by antonpug
var testObj = this.getView();
How can I check with DoJo (or just native JS) if testObj has callableFunctionbefore I actually try to call callableFunction()and fail if it isn't there? I would prefer a native-DoJo solution as I need this to work on all browsers.
如果 testObjcallableFunction在我实际尝试调用callableFunction()并失败之前，我如何使用 DoJo（或仅使用原生 JS）检查它是否存在？我更喜欢原生 DoJo 解决方案，因为我需要它在所有浏览器上工作。
回答by dfsq
You can call it like this:
你可以这样称呼它：
testObj.callableFunction && testObj.callableFunction();
or in details:
或详细说明：
if (typeof testObj.callableFunction == 'function') {
testObj.callableFunction();
}
回答by Craig Swing
dojo has a function that you can use to perform the test.
dojo 有一个可以用来执行测试的函数。
require(["dojo/_base/lang"], function(lang){
var testObj = this.getView();
if(lang.isFunction(testObj.callableFunction)){
testObj.callableFunction();
}
});
回答by jbabey
You should test that the property exists and is a function:
您应该测试该属性是否存在并且是一个函数：
var returnFromCallable = typeof testObj.callableFunction === 'function' &&
testObj.callableFunction();
